For a first-time visitor but longtime Anglophile, what’s essential to see and do in London?

Don’t spend too much time on the tube. It’s fast and convenient (and a marvellous piece of Victorian engineering) but its often better to walk if your journey is less than three stops. London is a delightful city to walk around, and you’re certain to see all sorts of interesting buildings on a 10 minute walk through any area. Get a data SIM for your phone and use your maps app to avoid getting lost and you’ll have the freedom to explore all kinds of interesting streets that most tourists who stick to the tube for everything completely miss.